This invention relates to a method and apparatus for roll forming products of complex shape and, more particularly, to a unique method and apparatus for fabricating on a continuous basis a roof ridge ventilator having an integral dam on a continuous basis.
Heretofore, various forms of roof ridge vents have been proposed. These roof ridge vents are mounted at the peak or ridge of a roof structure and are employed to provide natural attic ventilation in conjunction with soffit vents. Each ventilator section usually includes a hood portion or cover, generally horizontal, inwardly extending ventilation panels, downwardly extending inner side walls and flashing portions. An example of one such roof ridge ventilator may be found in commonly owned, copending U.S. application, Ser. No. 597,029, filed July 18, 1975 and entitled VENTILATOR FOR ROOF RIDGE, now U.S. Pat. No. 4,000,688, issued Jan. 4, 1977. As disclosed therein, the ventilator includes a hood portion, inwardly extending ventilation panels each having formed, integral with the inner lateral edge thereof and an upwardly extending dam. The dam is defined by a vertical lip and an inner vertical side wall, reverse reversedly bent and formed integral with the lip. The ventilation panel includes a plurality of longitudinally extending vent openings, transversely spaced across the panel. Each vent opening is hooded by an offset strap. The straps extend from the panel in alternate rows, offset oppositely from the panel. The central portion of each strap is generally parallel to the panel and must be formed by a double lancing process.
Roof ridge vents of the type illustrated in the aforementioned application have not been economically or commercially formable on a continuous basis from coiled aluminum stock by a rolling mill process. This has resulted primarily from problems encountered with forming the integral dam structure adjacent the ventilation panel. Once the ventilation panels have been lanced to form the vent openings, these panels cannot be touched by the forming apparatus. As a result, roof ridge vents including an integral dam structure have not been mass produced from aluminum stock due to the inherent fabrication problems. Although roll form apparatus such as that illustrated in U.S. Pat. No. 2,251,967 to Yoder entitled MACHINE FOR AND PROCESS OF FORMING STRUCTURAL MEMBERS and issued on Aug. 12, 1941, have been employed to fabricate a wide variety of products of complex shape, they have not been employed for the fabrication of roof ridge ventilators including integral dam structures.
A need therefore exists for a method and apparatus for fabricating roof ridge ventilators having integral dam structures on a continuous basis from coiled or sheet aluminum stock and which is economically and commercially practicable.